You probably missed it, but the nature.com article that some commenters have referenced [1] has more details, including information on the charge rate.
> A full-cell incorporating graphene balls increases the volumetric energy density by 27.6% compared to a control cell without graphene balls, showing the possibility of achieving 800 Wh L−1 in a commercial cell setting, along with a high cyclability of 78.6% capacity retention after 500 cycles at 5C and 60 °C.
In your other comment you write:
>the standard is 80% capacity after 500 cycles at the normally specified (1C) charge rate
So I'd say that's pretty good.